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Show 92 ACRE Dependencies on Signal Frequencies Signal frequencies can affect the equations used in an ACRE analysis, but because ACRE is separate from the equations programmed in it, the frequencies do not affect ACRE per se. The equations for very high frequency circuits deal with the skin effect on the conductors while the equations for lower frequency signals deal with the bulk effect of the conductors. At frequencies above 50 Mhz the transition between the two types needs to be made. At a much higher frequency, in the microwave range above 20 Ghz, signals need rounded corners in the paths or they tend to leak out, and ACRE can not handle the all angle designs incorporated into a circuit for that. Because the measurements of a circuit are static, ACRE can apply those measurements to formulae for any frequency that is compatible with Manhattan layout. ACRE Analysis with Different Kinds of Circuits ACRE was envisioned as an analysis tool for larger circuits when a hierarchical implementation was planned, but when it became a flat layout analysis tool, it became restricted to layouts that fit into one cell. A size restriction of 1 OK transistors and 1 OOK polygons or paths is roughly suitable to an analysis that takes ten Mbytes of memory and one hour of time on a ten MIPS system. Because the program being run ultimately determines the run time and memory usage, these numbers are very rough for a program that performs three to four passes through the data to determine area, neighboring geometries, and output a condensed report of fringing conditions. The target |
